Creating a NLP driven chatbot
The deeplearning.ai Natural Language Processing Specialization, is a great place to start. It'll brush up some basic concepts of NLP and then get into SOTA methods  such as Transformers. There's even a project in one of the courses about building a chatbot using transformers, it also has a ton of papers and other sources mentioned.

Rasa is a great software tool/package to get started with chatbots too. It's a great engaging community so your queries should be quickly answered.